Production potential,biodiversity and soil properties of forest reclamations: Opportunities or risk of introduced coniferous tree species under climate change?

European Journal of Forest Research - In the time of ongoing climate change and the increasing area of post-mining landscape, the successful afforestation of reclamation sites by suitable adaptive...     

Back to the roots: how do seedlings of native tree species react to the competition by exotic species?

Context

Identifying the traits of exotic species may explain their invasiveness and help control the negative impacts of these species on native ecosystems. In this study, we investigated root competition as an important driver for the competitiveness of two exotic tree species in the seedling stage.

Aims

In a pot experiment, carried out in Central Europe, we studied the effect of root competition of two exotic tree species (Prunus serotina Ehrh. and Robinia pseudoacacia L.) on biomass allocation of two native ones (Quercus robur L. and Carpinus betulus L.).

Methods

Seedlings of these species were exposed to intra- and interspecific mixtures with and without the effect of root competition. For this, belowground plastic partitions were installed in the pots.

Results

Competition intensity in the pots increased over time, irrespective of mixture type. However, this increase was much higher for the native species if mixed with the exotic species compared to monocultures or inter-native mixtures. In addition to ontogeny, competition affected biomass allocation patterns. Under root competition by the exotic species, the native species preferentially allocated their biomass to the roots. A higher allocation to the roots was mainly achieved at the expense of leaf and branch biomass.

Conclusion

Root competition of P. serotina and R. pseudoacacia may be a reason for the lack of Q. robur and C. betulus in the seedling stage in natural environments where all four species occur.     

Filling the "vertical gap" between canopy tree species and understory shrub species:biomass allometric equations for subcanopy tree species

Subcanopy tree species are an important component of temperate secondary forests.However,their biomass equations are rarely reported,which forms a "vertical gap" between canopy tree species and understory shrub species.In this study,we destructively sampled six common subcanopy species(Syringa reticulate var.amurensis(Rupr.) Pringle,Padus racemosa(Lam.) Gilib.,Acer ginnala Maxim.,Malus baccata(Linn.) Borkh.,Rhamnus davurica Pall.,and Maackia amurensis Rupr.et Maxim.) to establish biomass equatio...     

Dynamics of dominant tree species in a forest ecotone on the northern slop of Changbai Mountain

The competition and dynamics of dominant trees species in the forest ecotone between the broad-leaved/Korean pine （Pinus koraiensis） mixed forest and the spruce-fir forest （also known as dark conifer forest） in Changbai Mountain, Jilin Province in Northeast China were studied by using Lotka-Volterra model, based on the data from twenty-eight sample plots with area of 20 mx90 m for each one. Results showed that under natural condition, differentiation of communities followed two directions： one would be Spruce （Picea jezoensis and few P. koraiensis） and fir （Abies nephrolepis） co-dominant conifer forest, and at the equilibrium fir was absolutely preponderant （77.1% of relative dominance （RD））; the other would be the conifer and broad-leaved mixed forest, and at equilibrium, the broad-leaved tree species was 50% of RD in the broad-leaved/Korean pine mixed forest and 66% of RD in the broad-leaved and spruce-fir mixed forest. The study demonstrated that both broad-leaved/Korean pine mixed forest and dark conifer forest were climax community, the ecotone had transitional characteristics, and the diversification of the forest communities suggested that the direction of succession was affected by local habitat.     

Responses of the seedlings of five dominant tree species in Changbai Mountain to soil water stress

Soil water stress was studied on the potted seedlings of five dominant tree species (Pinus koraienes Sieb.et Zucc.,Fraxinus mandshurica Rupr., Juglans mandshurica Maxim, Tilia amurensis Rupr. and Quercus mongolica Fisch.ex Turcz) from the broadleaved/Korean pine forest in Changbai Mountain. Leaf growth, water transpiration and photosynthesis were compared for each species under three soil moisture conditions: 85%-100% (high water, CK), 65%-85% (Medium water, MW) and 45%-65% (low water, LW) of 37.4% water-holding capacity in field. The results showed that the characteristic of typical drought-resistance of the leaves is significantly developed. The net photosynthetic rate and water use efficiency of Fraxinus mandshurica were higher in MW than those in CK. But for the other four species, the net photosynthetic rate and water use efficiency in CK were lower than those in MW and LW. The transpiration rate responding to soil moistures varied from species to soecies.     

Effect of three tree species on UV weathering of wood flour-HDPE composites

Eucalyptus urophylla, Acacia mangium, and Pinus caribaea are the primary species for the wood industry in Vietnam. Wood residues of these species were used to reinforce high-density polyethylene(HDPE) composites. The flexural or bending property, impact strength and surface color were evaluated after exposure to accelerated ultraviolet weathering up to 2000 h. The weathered surface was characterized by scanning electron microscopy(SEM) and Fourier transform infrared(FTIR) spectroscopy. The results indicate that A. mangium/HDPE composites had the lowest color change and least fading,and remained stable after 1500 h exposure. FTIR spectroscopy showed that the oxidation of the composites increased in parallel with duration of exposure by assessing the concentration of carbonyl groups on the surfaces. SEM showed that all three species reinforced composites exhibited similar severe cracks after 1000 h;however, at the end of the weathering test, E. urophylla and P. caribaea composites were more severely cracked than A. mangium composites. A. mangium also had the highest flexural strength, impact strength and crystallinity duringweathering. A. mangium is the most preferable among the three species to reinforce HDPE.     

Research advances in the study of Pistacia chinensis Bunge, a superior tree species for biomass energy

As a renewable energy, biomass energy has aroused wide attention and studies of this issue have become a hot topic throughout the world. Pistacia chinensis Bunge (Anacardiaceae) is a superior species for biomass energy with high oil content in seeds and wide geographic distribution. It is a dioeciously, deciduous arbor, flowering from March to April and bearing fruits from September to November. The classification, regional distribution and biological characteristics of P. chinensis are stated in this paper, then, research advances in the growth, breeding and physiology of this species are summarized. The problems in present studies are broached. Finally, a future direction for research is proposed.     

Quantification of tree species diversity in forest stands—model BIODIVERSS

This paper presents a method for complex evaluation and quantification of tree-layer species diversity in forest ecosystems—model BIODIVERSS. The model was constructed for the assessment of species diversity on a small-scale (forest-stand) level, but may be applied with advantage to regional and large-scale inventories. The probability of correct classification of species diversity degree is relatively high; e.g. with a sampling intensity of only 1.5%, the correctness of the classification by the model is already 90%. Model BIODIVERSS is a simple and practical tool. It can be used directly during fieldwork, since for its application only a pocket calculator is needed.     

The tree species matrix,influence on the level of herbivore browsing in mixed forest stands in southwest Sweden†

Herbivory pressure on a forest stand and each plant individual may be affected by the spatial distribution of conspecific and allospecific plants on the site; whether the plants are standing in solitary or groupwise settings; or by the differences in the preference of plants in relation to each other. The study was conducted in southwest Sweden, where 120 plots (1508?m²) were visited and 1280 individual woody plants evaluated and measured. We tested the hypothesis that preferred woody plants can protect unpreferred conspecific and allospecific woody species against herbivory in a system with one dominant, generalist herbivore, the fallow deer (Dama L.), and that the effectiveness of this protection varies depending on the relative preference of the neighboring conspecific and allospecific woody species placed in conspecific groups or standing solitary. Our results support the hypothesis that preferred woody plants can protect unpreferred conspecific and allospecific woody species against herbivory in the case of Picea abies dominating stands.     

Planting six tree species on soda-saline-alkali soil

IntroductionThereareabout2,ooo,ooohm2Ofsoda-saline-alkaIisoilinSonglunpIaininHeiIongjiang(Shen1998).ltisdistributedmainlyinZhaodong,Zhaozhou,Zhaoyuan,Anda,Daqing,Duerbuteandothercountiesandcities.FormerIy,therewerenotreesonsoda-saline-alkaIisoil.CropscannotgrowonsuchsoiIs.PIantingtreesonthesesoilsmightimproveonitsquaIity(LingetaI1982).TostudypIantingonsoda-saline-aIkalisoiIhassignificanceforestablishingprotectivepIantationsystemofgrasslandandestabIishingperfectprotec-tivepIantations…     

Drought tolerance of Acacia karroo, a native tree species to South Africa, in Beijing

Acacia karroo is an indigenous, strong drought-tolerant and widely planted tree in South Africa. In order to match the plant with its adaptation to forest sites in China, it is important to know the drought-tolerance of this species under Chinese forest site conditions. Our study was carried out in cinnamon soils in Beijing and with Platycladus orientalis, the most drought-tolerant tree in Beijing, as control. Physiological parameters of young plants of the trees were measured and divided into three groups in response to soil drying. The first group included root activity, ABA content in roots and peroxidase (POD) activity in leaves. Their values changed similarly to those of P. orientalis and dramatically increased to maximum values when the soil water content (SWC) decreased from its normal level of 20% to 7.6% where the three indices decreased dramatically when SWC was reduced further from 7.6%. The second group of parameters included the contents of proline, soluble protein and malondialdehyde (MDA). Their values showed greater variation than those of P. orientalis and significantly increased when SWC decreased from 20% in response to soil drying. However, the proline and soluble protein contents fluctuated in A. karroo at a lower level than those in P. orientalis. In contrast, the content of MDA in A. karroo was much higher than that in P. orientalis which almost did not increase in the drying soil. The third group of parameters consisted of soluble sugar, superoxide dismutase (SOD) and catalase (CAT). These parameters showed greater diversity and fluctuations among the three varieties of A. karroo compared with the control in response to soil drying. These results suggest that A. karroo is characterized as a strong, drought tolerant species in most of physiological parameters but weaker than P. orientalis in membrane lipid antioxidation.     

Response of seedlings of different tree species to elevated C02 in Changbai Mountain

Eco-physiological responses of seedlings of eight species,Pinus koraiensis, Picea koraiensis, Larix olgensis, Populus ussuriensis, Betula platyphylla, Tilia amurensis, Traxinus mandshurica andAcer mono from broadleaved/Korean pine forest, to elevated CO₂ were studied by using open-top chambers under natural sunlight in Changbai Mountain, China in two growing seasons (1998–1999). Two concentrations of CO₂ were designed: elevated CO₂ (700 μmol·mol⁻¹) and ambient CO₂ (400 μmol·mol⁻¹). The study results showed that the height growth of the tree seedlings grown at elevated CO₂ increased by about 10%–40% compared to those grown at ambient CO₂. And the water using efficiency of seedlings also followed the same tendency. However, the responses of seedlings in transpiration and chlorophyll content to elevated CO₂ varied with tree species. The broad-leaf tree species were more sensitive to the elevated CO₂ than conifer tree species. All seedlings showed a photosynthetic acclimation to long-term elevated CO₂. Foundation item: The project was supported by National Key Basic Development of China (G1999043400) and the grant KZCX 406-4, KZCX1 SW-01 of the Chinese Academy of Sciences Biography: WANG Miao (1964-), maie, associate professor in Institute of applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. China. Responsible editor: Song Funan     

Does future climate change facilitate expansion of evergreen broad-leaved tree species in the human-disturbed landscape of the Korean Peninsula? Implication for monitoring design of the impact assessment

To quantitatively assess future change of evergreen broad-leaved tree species’ distributions in human-disturbed landscapes of the Korean Peninsula under climate change, potential habitats (PHs) were projected for four important evergreen broad-leaved tree species (Quercus acuta, Castanopsis sieboldii, Machilus thunbergii, and Neolitsea sericea) by species distribution models (SDMs). The distribution data (presence/absence) of the target species in Korea and Japan were used as response variables for SDMs, and climatic data were used as explanatory variables. Three general circulation models under A2 emission scenarios were used as future climate scenarios for the years 2070–2099. Potential habitats masked by land-use data (PHLUs) were projected to assess the impact of anthropogenic activities. Highly accurate SDMs were obtained for all the target species. The current PHs were decreased to 21–35 % by the anthropogenic activities. Future PHLUs for all the target species were projected to increase by 2.0–18.5 times of current PHLUs. These results suggest that all the target species are applicable as indicator species for monitoring in the Korean Peninsula, even if anthropogenic effects are incorporated. Variation of the increasing rate was caused by the differences in the response to temperature changes. M. thunbergii responded sensitively to the increase of minimum temperature of coldest month and had a largest increase in PHLUs under future climate. Therefore, M. thunbergii is considered to be most appropriate species for monitoring the changes of horizontal distributions above all focal evergreen broad-leaved tree species.     

Does tree species composition control the soil carbon stocks of the Hyrcanian forest in the Northern Iran？ （A case study in Guilan province,Iran）

This work studied the effects of tree species composition on soil carbon storage in five mixed stands dominated by oriental beech and grown in the western Caspian region in Guilan province, called Astara, Asalem, Fuman, Chere and Shenrud. The thickness of the litter layer, soil characteristics, tree composition and percentage of canopy coverage were measured in each stand. Total soil organic carbon differed significantly by stand. Total （organic） carbon stores at Fuman, which had the lowest tree species richness with 2 species and least canopy coverage （75%）, were significantly （p〈0.05） higher than at other locations. Carbon stor-age in topsoil （0-10 cm） was significantly lower in Shenrud, which had the highest tree species richness with 5 species and highest canopy cov-erage （95%）. The high percentage of canopy coverage in Shenrud proba-bly limited the conversion of litter to humus. However, in the second soil layer （10-25 cm）, Asalem, with high tree species richness and canopy coverage, had the highest carbon storage. This can be explained by the different rooting patterns of different tree species. In the Hyrcanian forest. According to the results, it can be concluded that not only tree composi-tion but also canopy coverage percentage should be taken under consid-eration to manage soil carbon retention and release.     

Division of ecological species groups and functional groups based on interspecific association — a case study of the tree layer in the tropical lowland rainforest of Jianfenling in Hainan Island, China

Twenty-three sample plots dominated by Vatica mangachapoi at various elevations in the tropical lowland rainforest in the Jianfengling National Nature Reserve of Hainan Island were established. The interspecific association among the 32 dominant species was analyzed and the division of ecological species groups and functional groups are discussed. The results showed that these dominant populations had an overall positive interspecific association. The species pairs with significant, positive association accounted for only about 10% of the total 496 species pairs. Most of the other species pairs showed weak association or non-association, i.e., the dominant populations investigated had relatively independent distributions. The 32 dominant species were divided into four ecological species groups and ten functional groups according to their interspecific association coefficients, based on a cluster analysis of the species. Recognition characteristics of the ten functional groups are proposed. __________ Translated from Scientia Silvae Sinicae, 2007, 43(4): 9–16 [译自: 林业科学]     

Multiple disturbance patterns and population structure of a tropical tree species,Afzelia africana (Leguminosae–Caesalpinioideae), in two contrasting bioclimatic zones of the Republic of Benin

Understanding how multiple disturbances affect species population structure is crucial for designing a better conservation strategy of threatened species. In this paper, we assessed the disturbance patterns and evaluated their effects on the population structure of Afzelia africana, in two different bioclimatic zones of the Republic of Benin. The main disturbances in the studied area included branch pruning and debarking. Individuals of medium size (20–40 cm) were mostly pruned and debarked. The percentages of pruning and debarking were similar at population level across the two studied bioclimatic zones (t = ?0.04, p = 0.96; t = 0.73, p = 0.48). Examining this at individual level, pruning was similar but debarking was higher in the Sudanian zone (12.14 ± 0.93%) than in the Sudano-Guinean zone (7.44 ± 0.88) (W = 40859, p < 0.001). Population structure was bell-shaped in the Sudanian zone regardless of the disturbance level. In contrast, in the Sudano-Guinean zone, mildly disturbed populations showed an inverse J-shaped structure, whereas those highly disturbed were bell-shaped. This underlined the climatic (dryness) and disturbance effects on the establishment and recruitment of small trees into the next life stage in tropical savanna ecosystems. Good regeneration pattern and the largest individuals were found within the protected areas, demonstrating the prominent role of protected areas for the species conservation. Therefore, we suggested that conservation efforts should be extended to populations outside the protected areas. Forestry department should establish firebreaks networks to protect small individuals and facilitate their recruitment, as well as the regulation and enforcement should be improved on the sustainable use of the species.     

Unraveling the tripartite interactions among the woolly poplar aphid,its host tree,and their environment: a lead to improve the management of a major tree plantation pest?

Key message

For an optimal deployment of poplar resistance to the gall-inducing aphid Phloeomyzus passerinii , a laboratory susceptibility assay has been developed. The nature of aphid–tree interactions during compatible and incompatible situations has been studied in detail. This should help at identifying specific resistance markers and at testing effects of site conditions on tree–pest interactions.

Context

P. passerinii is a major pest of poplar plantations in Europe, and the plantation of resistant poplar genotypes is regarded as the best long-term management strategy for this pest. This requires a sound knowledge of the interactions among the pest, its host and their environment.

Aims

Here, we review the recent advances aiming at developing an optimal deployment of host resistance versus P. passerinii.

Results

Investigations on aphid-host interactions demonstrated that P. passerinii induces pseudogalls within the bark of susceptible hosts. This results in a reduction of starch bark content during aphid outbreaks, which could be involved in tree death. The constitutive level of starch in the bark could be related to the tolerance level of trees. A susceptibility test has been designed for poplar genotypes, discriminating three categories of susceptibility depending on tree’s ability to totally or partially inhibit pseudogall induction. The test still has several limitations however. It neither takes into account the large level of individual genetic diversity of the aphid in France, nor the environmental modulation of tree resistance and tolerance, while water deficit and fertilization could potentially affect these parameters.

Conclusion

The hypotheses drawn regarding the processes leading to tree death or resistance should help at identifying resistance markers, and at testing effects of site conditions on tree–pest interactions.

     

Predicting site productivity of the timber tree Pterocarpus angolensis§

Pterocarpus angolensis is an important timber tree of the miombo woodlands of sub-Saharan Africa. The species only grows in natural mixed forests and little is known about is productivity potential. This study aimed at investigating productivity of P. angolensis on a local scale in Namibia and Angola and on a regional scale in southern Africa. The most commonly accepted productivity indicator is stem diameter increment and this was used to study productivity at a regional scale. Indicators of productivity used at the local scale were basal area, proportional basal area and site form, which were derived from 217 forest inventory plots in Namibia and Angola. The productivity measures were modelled with abiotic site factors; biotic factors were added for the local scale. Results indicated that the most consistent site factors at local and regional scale were not related to climate but to forest cover, with the species having a competitive advantage in more open forests. Mean annual diameter increment in the open forests of Namibia was 0.51 cm after 50 years. Boosted regression tree models at a local scale showed that species presence can be modelled more successfully than species basal area, proportional basal area (correlation of 0.72 vs 0.56 and 0.45, respectively) and site form. The sites with the highest productivity of P. angolensis at the local scale had a temperature seasonality below 34.5 °C, a slope of less than 1.5°, tree cover less than 20% and stand basal area higher than 9 m² ha^?1. The results can assist in establishing a site-dependent growth model for the species and direct forest and fire management towards the most productive areas.